Connection for blade terminals



July 9, 1968 w. P. STEWART E L 3, 9

CONNECTION FOR BLADE TERMINALS Filed Jan. 10, 1967 United States Patent3,392,357 CONNECTION FOR BLADE TERMHQALS William Park Stewart, Seaford,and James Warfield Williams, Laurel, Del., assignors to E. I. du Pont deNemours and Company, Wilmington, Del., a corporation of Delaware FiledJan. 10, 1967, Ser. No. 608,292 5 Claims. (Cl. 337-187) ABSTRACT OF THEDISCLOSURE Tapered inserts hold the blade-type terminals of an electriccomponent wedged into tapered ra bbets in conductive adapters. A jackingfeature associated with each insert facilitates its easy removal forreplacement of the component.

This invention relates generally to the transmission of electric powerand, more particularly, to the manner in which circuits are fused.

Current-limiting fuse holders with spring clips to hold the fuses inplace and provide an electrical connection are known. However, availableholders of this type are not satisfactory in industrial applicationswhere high current in the range of 60 to 600 amps is required becausedissipated heat tends to anneal the clips and cause a progressivefailure of the connection. Consequently, current-limiting fuses areoften bolted to terminal connectors, thus insuring a tight connectionthroughout the service life of the fuse. Replacement of bolted fuses istime-consuming and requires the use of wrenches to make the necessaryconnections.

Such difliculties have been avoided and the advantages disclosed hereinhave been achieved with a fuse holder which includes a channel-shapedsupport member and a conducting adapter at each end of the channelmember, each adapter having a tapered rabbet. A tapered insert iscarried in each rabbet and telescoped on a bolt threaded into theadapter. Means are provided to positively engage the inserts in therabbets with a wedging action which insures a tight electricalconnection between blade terminals on the fuse, the inserts and theadapters and to release the wedging action for removal of the terminals.

Structural details of a preferred embodiment will become apparent in thefollowing specification wherein reference is made to the accompanyingdrawing. In the drawing, FIGURE 1 is a perspective view of the fuseholder and a blade-type current-limiting fuse; FIG. 2 is a fragmentarytop view showing one end of the holder and a fuse; and FIG. 3 is apartially sectioned end view of the fuse and holder.

In the illustrated embodiment, a fuse .10 having bladetype terminals 12is shown positioned in a fuse holder or circuit connection 14. Eachblade 12 is fitted between a tapered insert 16 and an adapter 18. Eachinsert 16 has a bolt hole therethrough and is held in place by the head19 on a bolt 20. Heads 19 are wing nuts threaded on the upper ends ofbolts 20 and held against relative rotation by lock pins.

Circuit connection 14 also has a channel-shaped support member 22 madefrom an insulating material to allow mounting close to ground or otherconductors. At each end of support 22, an adapter 18 is held by suitablefasteners. The adapter shown in FIGS. 2, 3 has a convergent longitudinalrabbet defined by surfaces 24, 26, 28,

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with surface 26 tapered inwardly to the bottom surface 24 and withsurface 28 perpendicular to surface 24. Bolt 20 is threaded into atapped hole 30 in the bottom of adapter 18. Bolt 20 has an integralcollar flange 32 between insert 16 and rabbet surface 24.

Adapters 18 and inserts 16 are made from electrically conductivematerial such as copper. Each adapter 18 has a binding post or screw 29which is adapted to receive a terminal connector in the circuit to befused.

Circuit connection 14 is assembled by placing fuse 10 in support 22 andfitting each blade terminal 12 between an insert 16 and the rabbetsurface 28 of an adapter 18, with the blade resting on surface 24 of theadapter. As head 19 is rotated clockwise by hand, insert 16 is forcedagainst surface 26 in a wedging action which insures a tight electricalconnection. In removing the fuse 10, head 19 is turned counterclockwise,which results in bolt 20 backing out of threaded aperture 30 untilcollar 32 is forced against insert 16. The resultant jacking forceloosens the tight connection between insert 16, blade 12 and adapter 18to such an extent that the fuse may be lifted from connection 14.

Among the advantages of the illustrated connection is the manner inwhich fuse 10 is isolated from other electrical equipment by theinsulating support 22 and thereby provides for more compact electricalinstallations. The support may also be part of a molded-case circuitbreaker using current-limiting fuses. The taperedrabbet-insert-assemb'lies not only hold the blade terminals in a visegrip but also allow for insertion and removal of the fuse, using onlythe fingers, in a minimum of time and without the use of tools.

The connection is useful for any fuse or other type of electriccomponent which has fiat or leaf-like terminals. Instead of a head 19, alever-operated camming action could be provided to position each insert16. Alternatively, when the fuse holder is located in a closelyconfined, hard-to-reach space, a hex nut may be substituted for wing nut19 so that a socket and extension may be used to reach and position theinserts. Other changes and modifications of a similar nature will occurto those skilled in the art without departing from the spirit of thisinvention which is accordingly intended to be limited only by the scopeof the appended claims.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. A connection for blade terminals, said connection comprising: achannel-shaped support of insulating material; a conducting adaptermated with and mounted in the support and provided with a taperedrabbet; a tapered insert having a bolt hole therethrough, there being athreaded aperture in said adapter adapted to register with the bolthole; and a bolt extending through said hole into the threaded aperture,said bolt being adapted to wedge the insert against a blade terminallocated in the rabbet and having an integral flange between the adapterand insert for jacking the latter away from the adapter.

2. A circuit connection for an electric component having bladeterminals, said connection comprising: a channel-shaped support ofinsulating material; a spaced pair of conducting adapters mated with andmounted in the support, each provided with a tapered rabbet; a pair oftapered inserts, each having a bolt hole therethrough, there beingthreaded apertures in said adapters adapted to register with the boltholes; and a bolt extending through each hole into an aperture, saidbolts being adapted to wedge the inserts against blade terminals locatedin the respective rabbets, each bolt having an integral flange be-References Cited tween its adapter and Insert for acking the latteraway- UNITED STATES PATENTS from the adapter.

3. The connection of claim 2 wherein the tapered 2,193,691 3/1940Johnson at 339270 bb are convergent 5 2,272,665 2/1942 Hammerly 3392704. The connection of claim 2 wherein the jacking flange 2,558,581 6/1951Powell et 70 XR on each bolt is a collar.

5. The connection of claim 2 wherein the bolt has a BERNARD GILHEANYP'jmm'y Examine)" head in the shape of a wing nut. H. B. GILSON,Assistant Examiner.

